Kleptoparasite

[brotherbear]

A kleptoparasite is an animal that routinely displaces accomplished predators from their kills. Some ( non-bear ) animals of the far distant past ( possibly ) includes Tyrannosaurus rex, Andrewsarchus, and Daeodon. The giant short-faced bears ( Arctodus and Arctotherium ) were probably kleptoparasites.

Feeding on Carrion and Prey of Other Predators
Brown bears are commonly consuming dead animals found by them (Zavatsky, 1979, Zyryanov, 1979, Kaletskaya, 1981, Zhiryakov, 1987 and Pazhetnov, 1990), including in Sikhote-Alin (Bromlei, 1965, Matyushkin, 1974, Darman, 1982, Yudin, 1993 and Zaitsev and Seryodkin, 2011). The results of the capture of bears conducted by us in the Sikhote-Alin Nature Reserve have shown that they are attracted to carrion (Seryodkin et al., 2005b). In 1992–2001 six brown bears were caught with the use of bait: three animals using meat bait and three — using fish bait. The rate of successful capture was much higher using these baits (560 days/individual), rather than using trails and marked trees (1196 days/individual). Meat baits are consumed by the animals in any season.

Besides dead and wounded animals bears eat the prey of other predators and the remnants of their meals in Sikhote-Alin. Most often, the bears consume prey of tigers and lynxes (Matyushkin, 1974, Kostoglod, 1976 and Seryodkin et al., 2005a). A case of using the prey of yellow-throated marten is known (Zaitsev, 1991). Large bears cannot only eat up remains after tigers, but also chase them off their prey or join the fight (Sysoev, 1966, Kucherenko, 1971, Kostoglod, 1976 and Seryodkin et al., 2005a). In the snow period some bears purposely track tigers and lynxes to find the remains or take away their prey (Kostoglod, 1976 and Seryodkin et al., 2012). According to observations of Kostoglod, the trail of a bear not settled in its lair tracking other predators in order to capture their prey was 22% of the total length of the bear trail (44 km out of 200 km) (Kostoglod, 1976). In the spring before snow melting bears look for animals which died during winter and prey of tigers buried in snow (Seryodkin et al., 2005a). For this purpose bears go along the floodplain of a river or a creek, often leaving the path to examine interesting places, winding, sometimes stopping to sniff. A bear is able to smell the odor of the remains of an animal at a distance of 250 m at a temperature below 0 °C. Bears also go in the footsteps of their relatives, picking uneaten remains of carrion. Snowtracking of three brown bears in the basin of a creek in the Sikhote-Alin Nature Reserve in April revealed that along the 17 km trail the bears have four times found the remains of red deer crushed by tigers during the winter, and once — a whole red deer that died of a broken limb. In three cases other bears have been on these tiger prey before them.

Behavior Near Prey or Carrion
Covering the prey with soil, forest cover, branches and other forest products is typical, but not necessary for brown bears in Sikhote-Alin (Matyushkin, 1974). The burial of the prey may be complete when the whole animal is hidden, or partial. Apparently, the act of covering primarily provides saving the prey from spongers, as the bear's prey attracts corvid birds, and the predator guards it from them (Pazhetnov, 1990). On the Kola Peninsula, burying of the remnants allows to distinguish the bear's prey from accidental carrion (Semyonov-Tyan-Shansky, 1972). For the Sikhote-Alin this assumption is not true. Out of 28 known cases of brown bears feeding on dead bodies of animals in 8 cases (28.6%) the burial occurred. Four times out of five bears were burying their prey, twice — the prey of tigers (out of 20), in both cases the tigers were chased off by the bears, and twice the bears buried dead wounded animals found by them. It is clear from these data that the bears are more likely to bury whole carcasses of animals rather than their remains left after other predators.
A brown bear may cover its prey after he had already started to eat it (Matyushkin, 1974), or after burying the carcass, may wait for some time without eating it. In the latter case, covering the prey with the forest cover by maintaining the temperature contributes to faster fermentation processes that make fresh meat “ripe” that is more attractive for animals (Korytin, 1998). We know of two cases when brown bears buried dead animals, but did not eat them at once. In the first case, a bear buried a dead wounded boar and returned to the place of burial on the third day. In another case, a brown bear that killed another brown bear covered it with forest cover and left the place without touching the food. For covering a red dear one of predators had to dig up and bring to the center the soil and forest cover from an area of 60 m2. The author also observed Kamchatka brown bears waiting for “ripening” of dead prey. A large male bear began to eat a buried female bear three days after procuring it at Kronotskaya River (Kronotsky Reserve) in September 2003. Reply